• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권12호
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• pp.601-605
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• 2006

The resistance-capacitance (RC) delay of signals through interconnection materials becomes a big hurdle for high speed operation of semiconductors which contain multi-layer interconnections in smaller scales with higher integration density. Low-k materials are applied to the inter-metal dielectric (IMD) materials in order to overcome the RC delay. Relaxation continuum (RCT) model that includes neutral-species transport model have developed to model the etching process in a capacitively coupled plasma (CCP) device. We present the parametric study of the modeling results of a two-frequency capacitively coupled plasma (2f-CCP) with $N_2/H_2$ gas mixture that is known as promising one for organic low-k materials etching. For the etching of low-k materials by $N_2/H_2$ plasma, N and H atoms have a big influence on the materials. Moreover the distributions of excited neutral species influence the plasma density and profile. We include the neutral transport model as well as plasma one in the calculation. The plasma and neutrals are calculated self-consistently by iterating the simulation of both species till a spatio-temporal steady state profile could be obtained.

• 융합경영연구
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• 제11권5호
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• pp.1-13
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• 2023

Purpose: This study analyzed the factors that increase the satisfaction of local residents' housing and residential environment, and derived implications for housing suppliers and policymakers in local areas. Research design, data and methodology: The analysis method derived latent group types through latent profile analysis, and cross-analysis and covariate variance analysis (ANCOVA) were conducted to analyze the differences between these groups. Results: The analysis results are as follows. First, there are four potential group types: good neighborhood facilities and low-level surrounding environment 1 group, low-level neighborhood facilities and good surrounding environment 2 groups, overall low-level 3 groups, and overall high-level 4 groups. Second, groups 1 and 3 tend to live in relatively old apartments. Third, as a result of distributed analysis, groups with low accessibility to neighborhood facilities but good environmental conditions and groups with high overall levels had relatively high housing satisfaction. Conclusions: As an implication, we discussed the need for development that highlights natural environment-friendly characteristics as well as access to neighborhood facilities. In addition, in order to derive more specific implications, the direction of follow-up studies considering job linkage and the effects of specific and various environmental factors was presented together.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.93-93
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• 2016

Large scale integrated circuits (LSIs) has been improved by the shrinkage of the circuit dimensions. The smaller chip sizes and increase in circuit density require the miniaturization of the line-width and space between metal interconnections. Therefore, an extreme precise control of the critical dimension and pattern profile is necessary to fabricate next generation nano-electronics devices. The pattern profile control of plasma etching with an accuracy of sub-nanometer must be achieved. To realize the etching process which achieves the problem, understanding of the etching mechanism and precise control of the process based on the real-time monitoring of internal plasma parameters such as etching species density, surface temperature of substrate, etc. are very important. For instance, it is known that the etched profiles of organic low dielectric (low-k) films are sensitive to the substrate temperature and density ratio of H and N atoms in the H2/N2 plasma [1]. In this study, we introduced a feedback control of actual substrate temperature and radical density ratio monitored in real time. And then the dependence of etch rates and profiles of organic films have been evaluated based on the substrate temperatures. In this study, organic low-k films were etched by a dual frequency capacitively coupled plasma employing the mixture of H2/N2 gases. A 100-MHz power was supplied to an upper electrode for plasma generation. The Si substrate was electrostatically chucked to a lower electrode biased by supplying a 2-MHz power. To investigate the effects of H and N radical on the etching profile of organic low-k films, absolute H and N atom densities were measured by vacuum ultraviolet absorption spectroscopy [2]. Moreover, using the optical fiber-type low-coherence interferometer [3], substrate temperature has been measured in real time during etching process. From the measurement results, the temperature raised rapidly just after plasma ignition and was gradually saturated. The temporal change of substrate temperature is a crucial issue to control of surface reactions of reactive species. Therefore, by the intervals of on-off of the plasma discharge, the substrate temperature was maintained within ${\pm}1.5^{\circ}C$ from the set value. As a result, the temperatures were kept within $3^{\circ}C$ during the etching process. Then, we etched organic films with line-and-space pattern using this system. The cross-sections of the organic films etched for 50 s with the substrate temperatures at $20^{\circ}C$ and $100^{\circ}C$ were observed by SEM. From the results, they were different in the sidewall profile. It suggests that the reactions on the sidewalls changed according to the substrate temperature. The precise substrate temperature control method with real-time temperature monitoring and intermittent plasma generation was suggested to contribute on realization of fine pattern etching.

• Nutrition Research and Practice
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• 제9권2호
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• pp.186-191
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• 2015

BACKGROUND/OBJECTIVES: Rheumatoid arthritis (RA) is associated with an excess mortality from cardiovascular disease which is likely attributed to an atherogenic lipid profile. Among nutritional factors vitamin K has been recently focused as a pivotal nutrient in improvement of lipid related markers. Thus, this study was designed to determine the effects of vitamin K on lipid profile in this disease. SUBJECTS/METHODS: Fifty eight patients with definitive RA were participated in the present double blind placebo controlled study. They were randomly allocated into two groups to receive vitamin $K_1$ as phylloquinone [10 mg/day] (n = 30) or placebo pills (n = 28), for eight weeks. In order to control the effects of probable confounders dietary intakes, anthropometric measurements including weight and height, clinical status using disease activity score-28 (DAS-28), physical activity and anxiety status were evaluated at baseline. Moreover, serum levels of lipid related markers including total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) were measured at baseline and at the end of intervention. RESULTS: There were no significant differences between the two groups regarding any of the baseline characteristics. After adjusting for some relevant confounders, in comparison between two groups, we observed no significant changes in lipid related markers at the end of intervention. Also, there was no significant difference between before and after intervention values within groups (P > 0.05). CONCLUSIONS: Function of vitamin $K_1$ in lipid profile modification remains still controversial. This study showed that vitamin $K_1$ has no effect on lipid profile in women with rheumatoid arthritis. Further studies with a longer follow-up are required to determine the effects of vitamin K on atherogenic lipid profile.

• 동의신경정신과학회지
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• 제3권2호
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• pp.65-85
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• 1992

To study the personality characteristics of alcoholic patients, they were screned with the MAST(Michigan Alcoholism Screening Test) and administered with the MMPI (Minnesota Multiphasic Personality Inventory) in the Dept. of Neuropsychiatry, Oriental Medical Hospital in Kyung Hee Univ. form March 1991 to June 1991. Patients admitted for alcoholism were examined and analyzed using the above tests and then studied by Sasang Constitutional approach. Results were as follows; 1. In the MAST score, the cases of obvious alcohol dependence was 53.3% and overall mean score was 28.1 point. 2. In the MMPI scale, the mean of the T-scores for 2(D)-4(Pd) profile was high, but it was not statistically significant. 3. The results obtained by multivariate cluster analysis of MMPI T-scores can be divided into 3 subgroups; 1) 9% showed the psychiatric tendency of F-6(Pa)-9(Ma)profile, 2) 44.2% showed no significant profile, 3)46.5% showed the neurotic tendency of 1(Hs)-2(D)-3(Hy)-4(Pd) profile. 4. Since 44.2% showed no significant profile on the MMPI, much more alcoholic patients were caused not by personality factors but by social tolerance, and also by increasing apportunities of drinking in Korean society. 5. When analyzed with Sasang Constituional approach, 1) for the Soyangin (少陽人): 6(Pa) scale was particularly high, 1(Hs) and 3(Hy) scales were low compared to others, 2) for the Taiumin(太陰人): 1(Hs)-2(D)-3(Hy)-4(Pd) neurotic profile was high, the K-scale and 4(Pd)scale were high compared to the Soyangin, 3) for the Soumin(少陰人): 1(Hs)-2(D)-3(Hy)-4(Pd) neurotic profile and 7(Pt) scale were also high.

• 한국정보기술학회논문지
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• 제17권4호
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• pp.87-97
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• 2019

SRS는 특정 센서 네트워크 및 센서 유형에 독립적으로 센서 데이터의 의미를 모바일 기기에 즉시적으로 처리하기 위해 제안되었다. 하지만 새로운 센서 데이터를 수신할 때 마다 센서 데이터 검사 연산을 반복적으로 수행하게 되어 성능 저하를 야기한다. 이러한 문제점을 해결하기 위해 앱 프로파일 기반 SRS가 제안되었다. 앱 프로파일 기반 SRS는 프로파일을 통해 SRS 문제점을 개선하였으나 가상 시뮬레이션 환경에서 실험이 이루어졌으며 이 후 실시간 환경에서 실험을 하였으나 동적인 다양한 요소들을 고려하여 실험하지 못했다. 따라서 이 논문은 사용자의 이동성, 센서 밀집도 등의 인자를 고려하여 실험 평가를 실제 환경에서 수행하고 실험 결과의 분석을 통해 앱 프로파일 기반 SRS의 성능을 평가한다. 그 결과 앱 프로파일 기반 SRS는 밀집도와 센서의 종류에 큰 영향을 받으며, 센서 노드 수는 영향을 받지 않는 것을 알 수 있다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.427-428
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• 2002

Clearance movements of engine piston are regarded very important because they cause impact vibrations as well as many tribological problems. Some of the major parameters that influence these kinds of performances are piston profiles, piston offsets and clearance magnitudes. In our study. computational investigation is performed about the piston movements in the clearance between piston and cylinder liner by changing the skirt profiles and piston offsets. Our results show that curved profile and more offset to thrust side have better performance with low side impact during the engine cycle.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.289.1-289.1
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• 2016

Germanium (Ge) with higher carrier mobility and a lower crystallization temperature has been considered as the channel material of thin-film transistors for display applications. Various methods were studied for crystallizaion of poly-Ge from amorphous Ge at low temperature. Especially Metal induced crystalliazation (MIC) process was widely studied because low process cost. In this paper, we investigate copper diffusion process of different thick (70 nm, 350 nm) poly-Ge film obtained by MIC process at various temperatures (250, 300, and $350^{\circ}C$) through atomic force microscopy (AFM), Raman spectroscopy, and secondary ion mass spectroscopy (SIMS) measurement. Crystallization completeness and grain size was similar in all the conditions. Copper diffusion profile of 370 nm poly-Ge film show simirly results regardless of process temperature. However, copper diffusion profile of 70 nm poly-Ge film show different results by process temperature.

• 대한기계학회논문집B
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• 제24권1호
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• pp.1-8
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• 2000

A modified low-Reynolds-number Reynolds stress model is developed for the calculation of drag-reducing turbulent flows induced by polymer injection. The results without polymer injection are compared with the results of direct numerical simulation to ensure the validity of the basic model. In case of drag reduction, profiles of mean velocity and Reynolds stress components, in two-dimensional channel flow, obtained with a proper value of viscosity ratio are presented and discussed. Computed mean velocity profile is in very good agreement with experimental data. And, the qualitative behavior of Reynolds stress components with the viscosity ratio is also reasonable.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권1호
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• pp.16-22
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• 2002

The Proposed contactless charger employs a Pair of neighboring Printed circuit board (PCB) windings as a contactless energy transfer device, thereby making it amenable to low-Profile designs and suitable for applications to the portable telecommunication/computing electroncis in which stringent requirements for height, space, and reliability have to be met. The performance of the proposed charger is confirmed with experiments on a prototype charger developed for cellular phones